/*
 * Copyright (c) 2024 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { ts, rule } from "qvog-dsl";

const SEVERITY = 2;
const DOC_PATH = 'docs/no-param-reassign.md';
const DESCRIPTION = 'Reassigning function parameters is not allowed because it can lead to unexpected behavior and reduce code clarity.';

export default rule()
  .match(ts.isBinaryExpression)
  .when(node => {
      // 1. 判断是不是赋值表达式
      if (node.operatorToken.kind !== ts.SyntaxKind.EqualsToken) {
          return false;
      }

      // 2. 左侧是否是标识符
      if (!ts.isIdentifier(node.left)) {
          return false;
      }

      const identifierName = node.left.text;

      // 3. 获取当前函数作用域
      let current = node.parent;
      while (current && !ts.isFunctionLike(current)) {
          current = current.parent;
      }
      if (!current || !ts.isFunctionLike(current)) {
          return false; // 不在函数内，忽略
      }

      // 4. 检查参数列表中是否有同名参数
      return current.parameters.some(param => ts.isIdentifier(param.name) && param.name.text === identifierName);
  })
  .report({
      severity: SEVERITY,
      description: DESCRIPTION,
      docPath: DOC_PATH,
  });
